Fire safety systems in buildings typically include networks of devices that detect fire conditions, devices that provide notification of fire conditions, and devices that perform specialized control operations during the existence of fire conditions. The primary fire detection equipment in such systems includes smoke detectors and pull stations.
Smoke detectors are well known in the art. Smoke detectors used in large scale fire safety systems typically employ obscuration sensors to detect the presence of smoke. The obscuration sensors in general measure the obscuration or cloudiness of the air. Obscuration may be measured and expressed as the inverse of clarity. Clarity decreases, and hence obscuration increases, in the presence of smoke. Ideally, if no smoke is present, then the obscuration measurement is minimized. In the presence of smoke, however, the obscuration measurement dramatically increases. If the obscuration measurement increases beyond a threshold, then the smoke detector generates an alarm signal.
However, in actual implementation, the obscuration sensors may accumulate dirt and other environmental substances that gradually increase the obscuration measurement value in the absence of smoke. Left unchecked, the accumulated dirt and debris can eventually cause the obscuration measurement to reach the alarm threshold, even in the complete absence of smoke or fire. Such obscuration due to non-fire condition related reasons, such as build-up of dirt, debris, or even misalignment of sensors, is referred to herein as ambient obscuration.
False alarms caused by ambient obscuration of smoke detectors are highly undesirable, as false alarms can create significant disruption to normal activities in a building.
To avoid such false alarms, smoke detectors may be periodically replaced when they exhibit significant ambient obscuration. Alternatively, smoke detectors may undergo periodic maintenance to remove the dirt and substances that can cause increases in the ambient obscuration measurement value. Because such maintenance is labor intensive, it is desirable to strike a balance between performing frequent, unnecessary maintenance, and performing too infrequence maintenance that can result in false alarms.
To this end, sophisticated building fire safety systems often employ smoke detectors that can communicate information relating to their need for maintenance. The information may include information regarding the ambient obscuration level as measured by the sensors in non-fire conditions. The maintenance related information for a plurality of smoke detectors may be displayed to a technician on a computer display. The maintenance technician then uses the information to determine which smoke detectors are in need of maintenance, if any. Such a system can reduce the cost related to unnecessary maintenance while still providing protection against false alarms caused by ambient obscuration.
A drawback of the maintenance information display systems in current fire safety systems is that such systems can produce maintenance information that is relatively non-intuitive to the technician or user. In particular, fire safety systems do not necessarily employ all of the same types of smoke detectors. Different types of smoke detectors often provide maintenance related information in different formats. Thus, when the information is displayed, a high level of system and smoke detector knowledge may be required to discern which smoke detectors require maintenance.
Moreover, even smoke detectors of the same type may employ different settings that affect the maintenance related information, resulting in increased complexity in assessing when the smoke detectors require maintenance.
Accordingly, there exists a need for a system that allows for more convenient and intuitive display of smoke detector maintenance information in a fire safety system that employs a plurality of models of smoke detectors.